Tuning apparatus



June 7, 1966 o. D. THURNELL 3,254,540

TUNING APPARATUS Filed Aug. 5. 1964 Inventor BY ORVILLE D. THURNELLWMMLQQL ATTYS.

United States Patent Filed Aug. 5, 1964, Ser. No. 387,667 8 Claims. (Cl.7410.8)

This invention relates generally to wave signal tuning apparatus, andmore particularly to an improved and compact tuning device which iseasily calibrated.

Certain applications for wave signal tuning apparatus may require thatsuch apparatus be compact, simple and very reliable. One suchapplication may be where wave signal tuning apparatus is utilized fortuning an individual radio receiver proximate a passenger seat in apassenger conveyance such as a bus, train or plane. Because a giventransportation company may own large numbers of conveyances, eachequipped with individual receivers proximate passenger seats,maintenance costs would be undesirably high unless the tuning apparatuswere very reliable in operation. Furthermore, minimum available spacedon most conveyances dictates that the apparatus be as compact aspossible. In addition, where such apparatus is to be operated byindividual passengers, simplicity of operation is.essential. Finally,because such apparatus may be installed in existing conveyances,installation must be possible to minimize the down time of theconveyance.

Accordingly, it is an object of this invention to provide an improvedtuning device which is simple of construction, compact, and reliable inoperation.

Another object of the invention is to provide wave signal tuningapparatus which is readily assembled and installed.

A feature of the invention is the provision of a rotatable indicatormember having indicia thereon for tuning indication and mounted suchthat indicia are visible through an opening in the mounting panel. Theindicator member is readily released from its driving mechanism for easycalibration.

Another feature of the invention is the provision of an indicator memberdriven by a pinion gear with the indicator member having crown gearteeth thereon spring biased into engagement with the pinion gear. Theindicator member is manually displaceable axially against the bias ofthe spring to be freely rotatable for calibration.

Still another feature is the provision of a pinion gear for operating atuner and an indicator member, which pinion gear is driven through aslip clutch by a rubber surfaced wheel in engagement with a manuallyturnable knurled knob.

In the drawing:

FIG. 1 is an end elevational view, partially in section, showing wavesignal tuning apparatus constructed in accordance with the invention andmounted on a panel;

FIG. 2 is a side elevational view thereof, partially in section;

FIG. 3 is a bottom plan view of the tuning apparatus;

FIG. 4 is a bottom plan view similar to FIG. 3 but wherein the indicatorwheel is disengaged from its driving gear; and

FIG. 5 is an exploded perspective view of a portion of the tuningapparatus of FIGS. 1-4.

In accordance with the invention, wave signal tuning apparatus isprovided with a tuner drive shaft rotatable to position tuning elements.Control means for rotating the tuner drive shaft are provided andinclude a manually operable knurled knob which engages and drives arubber surfaced wheel. The wheel drives a pinion gear through a slipclutch. The pinion gear has an axis of rotation "Icesubstantiallyperpendicular to the drive shaft. A crown gear engages thepinion gear and is drivingly connected to and coaxial with the driveshaft. An indicator wheel, having indicia thereon for indicating thefrequency to which the tuning elements positioned by the drive shaft aretuned, is mounted concentric with the crown gear. The indicator wheelhas crown gear teeth on one edge of its outer surface and these teethengage the pinion gear and turn the indicator wheel in a predeterminedrelationship to the crown gear and the drive shaft in response torotation of the pinion gear. The indicator member is axially biased bymeans of a spring to hold the crown gear teeth thereon in engagementwiththe pinion gear and is manually displaceable against the bias ofsuch spring to disengage the crown gear teeth and permit free rotationof the indicator wheel for calibration.

The wave signal tuning apparatus shown in the drawing is for tuning anAM radioreceiver mounted behind a panel in a bus, proximate a passengerseat therein. The apparatus includes a tuner frame 11, which carries theusual tuning coils for the radio receiver. Frame 11 also includes alinearly displaceable core carriage 12 which carries a plurality ofmovable cores 13. Cores 13 extend into the coils for tuning the sameaccording to the position of core carriage 12. Core carriage 12 ispositioned by means of a worm or screw 15, which is formed integral witha tuning shaft 17. Rotation of tuning shaft 17 causes worm 15 to drivethe core carriage, 12 and position the tuning slugs 13 for tuning theradio receiver. A tuner structure of the type described is disclosed ina copending application of Charles E. Lyon, Jr., Serial No. 231,060,filed October 15, 1962, now Patent 3,190,132 and assigned to theassignee of the present invention.

A mounting plate 21 is secured over one end of the tuning frame 11 andincludes an opening therein through which control shaft 17 passes. Plate21 has a right angle portion 22 thereon from which an integral arm 22aextends. The arm 22a has a control knob 23 pivotally mounted thereon.Control knob 23 extends downwardly through an opening in a framestructure 25 and protrudes through a further opening in a panel 27. Thusknob 23 may be turned manually by the finger of a passenger seatedproximate the receiver.

Knob 23 is knurled on its surface and engages a rubber surfaced pinionwheel 31. Pinion wheel 31 is drivingly connected through a slip clutchcomprised of plate 31a and spring 32 to pinion shaft 33. Spring32 isattached to pinion shaft 33 and engages plate 310 to provide apredetermined frictional engaging force therebetween. "A three sectionpinion gear 35 is mounted on shaft 33.

Shaft 33 is supported at one end by a saddle in right angle portion 22of plate 21, and at the other end by a saddle in an outwardly extendingflange 37. The shaft 33 is seated in position in the saddles by means ofa spring 38, which is mounted to plate 21 and extends over shaft 33.

The section of pinion 35 furthest from wheel 31 is engaged by a crowngear 41. Crown gear 41 has an integral sleeve 41a extending therefromwhich sleeve is keyed to a keyed portion 17a of control shaft 17 fordriving the same. Thus, when knob 23 is rotated manually, drive shaft 17will be rotated to position the cores 13 through the torque transmissionchain comprised of knob 23, wheel 31, plate 31a, spring 32, shaft 33,pinion 35, crown gear 41 and sleeve 41a. At the ends of travel of thecore carriage 12, the frictional engagement force between spring 32 andplate 31a will be overcome and although knob 23 is rotated further, nodamage or binding of parts will result.

In wave signal tuning apparatus of the type shown,

compactness is a prime consideration. The previously describedconstruction will, as may be seen, fulfill this requirement. The problemof providing adequate visual indication of the frequency to which theapparatus is tuned is also solved by the apparatus of the invention. Anindicator wheel 51 is provided with indicia on the outer surface thereoffor indicating the frequency to which the tuning elements or cores 13positioned by drive shaft 17 are tuned. Wheel 51 may be of moldedplastic and has a plurality of crown gear teeth 52 on one edge of itsouter surface. Wheel 51 has an integral sleeve 53 at the center thereofsuch that Wheel 51 may be mounted coaxially wtih gear 41 and tuningshaft 17. Sleeve 53 fits over sleeve 41a and is rotatable with respectthereto. The spring 55 is secured to the end of shaft 17 and biases thewheel 51 axial-1y along shaft 17, so that crown gear 41 is held inengagement with pinion 35, and so that crown gear teeth 52 also are inengagement with pinion 35.

The ratio between the number of teeth on crown gear 41 and the number ofcrown gear teeth 52 on Wheel 51 is selected such that wheel 51 will makeone complete revolution as core carriage 12 travels from one limit ofits travel to the other due to the driving of gear 41. A workable ratiobetween the number of teeth on crown gear 41 and crown gear teeth 52 hasbeen found at 20 to 95. Other ratios determined by the requirements ofthe system will, of course, be within the scope of the invention. Thedial markings or indicia on wheel 15 are calibrated with the position ofthe tuning elements by first tuning the apparatus to a predeterminedfrequency. Wheel 51 is then drawn outwardly to the position indicated inFIG. 4 so that crown gear teeth 52 disengage from pinion 35. Thispermits Wheel 51 to be freely rotated with respect to the shaft 17 suchthat the indicia may be positioned properly. Referring to FIG. 1, itwill be seen that the indicia on the surface of wheel 51 are visiblethrough an opening 27a, formed in panel 27 for this purpose. Thus, byproper calibration, the user of the apparatus may turn knob 23 andobserve the frequency to which the apparatus is tuned through opening27a. The units may be readily calibrated at the factory when they areassembled and if some deviation occurs during shipping or final mountinginto a conveyance, recalibration is easily accomplished.

Such a simple construction provides numerous advantages. The simplicitycarries with it an inherent reliability, reducing maintenance cost.Because of the simplicity of construction, assembly costs are alsoreduced. Where string or cable type dial indicators are used, complexfinal assembly operations are often necessary whereas with the presentinvention, final assembly is very simple. Crown gear teeth 52 and theteeth of pinion gear 35 are so designed that full gear mesh will notoccur. This permits full tooth engagement between the teeth of crowngear 41 and those of pinion 35 to minimize backlash. Were fullengagement between both the teeth of gear 35 and the teeth 52 withpinion 35 permitted, interference problems might result. The pressurewhich spring 35 applies to the wheel 51 is sufficient to cause crowngear teeth 52 to hold the pinion against the slip torque applied by theclutch consisting of plate 31 and spring 32. This prevents toothskipping which would affect the calibration of the apparatus.

It may therefore be seen that the invention provides improved wavesignal tuning apparatus which is simple and compact of construction andmay be readily calibrated.

What is claimed is:

1. Wave signal tuning apparatus including in combination, a tuner driveshaft rotatable to position tuning elements, control means coupled tosaid drive shaft for rotating the same, said control means includingtorque transmitting means turning in a predetermined relationship tosaid drive shaft, and an indicator member having an outer surface withindicia thereon for indicating the frequency to which the tuningelements positioned by said drive shaft are tuned, said indicator memberhaving means on one edge of said outer surface thereof in engagementwith said torque transmitting means and turning said indicator member ina predetermined relationship to the rotation of said drive shaft inresponse to rotation of said torque transmitting means, said indicatormember being axial-1y displaceable to disengage from said torquetransmitting means to permit said indicator member to be turned freelyfor calibration.

2. Wave signal tuning apparatus including in combination, a tuner driveshaft rotatable to position tuning elements, control means coupled tosaid drive shaft for rotating the same, said control means including agear turning in a predetermined relationship to said drive shaft, and anindicator member having indicia thereon for indicating the frequency towhich the tuning elements positioned by said drive shaft are tuned, saidindicator member having gear teeth in engagement with said gear andturning said indicator member in a predetermined relationship to therotation of said drive shaft in response to rotation of said gear, saidindicator member being displaceable to disengage said gear teeth fromsaid gear to permit said indicator member to be turned freely forcalibration.

3. Wave signal tuning apparatu's including in combination, a tuner driveshaft rotatable to position tuning elements, control means for rotatingsaid drive shaft, said control means including a first gear having anaxis of rotation substantially perpendicular to said drive shaft, asecond gear engaging said first gear and being drivingly connected toand coaxial with said drive shaft, an indicator member having indiciathereon for indicating the frequency to which the tuning elementspositioned by said drive shaft are tuned, said indicator member beingconcentric with said second gear and having gear teeth about itsperiphery, said gear teeth being in engagement with said first gear andturning said indicator member in a predetermined relationship to saidsecond gear and said drive shaft in response to rotation of said firstgear, said indicator member being axially displaceable to disengage saidgear teeth from said first gear to permit free rotation of saidindicator member for calibration.

4. Wave signal tuning apparatus including in combination, a tuner driveshaft rotatable to position tuning elements, control means coupled tosaid drive shaft for rotating the same, said control means including apinion gear turning in a predetermined relationship to said drive shaft,an indicator member having an outer surface with indicia thereon forindicating the frequency to which the tuning elements positioned by saiddrive shaft are tuned, said indicator wheel having crown gear teeth onone edge of said outer surface thereof in engagement .with said piniongear and turning said indicator wheel in a predetermined relationship tosaid drive shaft in response to rotation of said pinion gear, and springmeans resiliently biasing said crown gear teeth of said indicator wheelin engagement with said pinion gear, said indicator wheel being manuallydisplaceable axially against the bias of said spring means to disengagesaid crown gear teeth from said pinion gear and permit said indicatorwheel to rotate freely for calibration.

5. Wave signal tuning apparatus including in combination, a tuner driveshaft rotatable to position tuning elements, control means for rotatingsaid drive shaft, said control means including a pinion gear having anaxis of rotation substantially perpendicular to said drive shaft, acrown gear engaging said pinion gear and being drivingly connected toand coaxial with said drive shaft, and an indicator member having anouter surface with indicia thereon for indicating the frequency to whichthe tuning elements positioned by said drive shaft are tuned, saidindicator member being concentric with said crown gear and having gearteeth on one edge of said outer surface thereof, said gear teeth beingin engagement with said pinion gear and turning said indicator member ina predetermined relationship to said crown gear and said drive shaft inresponse to rotation of said pinion gear, said indicator member beingdisplaceable to disengage said gear teeth from said pinion gear andpermit free rotation of said indicator member for calibration.

6. Wave signal tuning apparatus including in combination, a tuner driveshaft rotatable to position tuning elements, control means for rotatingsaid drive shaft, said control means including a pinion gear having anaxis of rotation substantially perpendicular to said drive shaft, acrown gear engaging said pinion gear and being drivingly connected toand coaxial with said drive shaft, an indicator wheel having an outersurface with indicia thereon for indicating the frequency to which thetuning element's positioned by said drive shaft are tuned, saidindicator wheel being concentric with said crown gear and having crowngear teeth on one edge of said outer surface thereof, said crown gearteeth being in engagement with said pinion gear and turning saidindicator member in a predetermined relationship to said crown gear andsaid drive shaft in response to rotation of said pinion gear, springmeans =bia'sing said indicator Wheel with said cro wn gear teeth thereonin engagement with said pinion gear, said indicator wheel being manuallydisplalcealble axially to disengage said crown gear teeth from saidpinion gear to permit free rotation of said indicator wheel forcalibration.

7. Wave signal tuning apparatus including in combination, a tuner driveshaft rotatable to position tuning elements between first and secondpositions, control means for rotating said drive shaft, said controlmeans including a pinion gear having an axis of rotation substantiallyperpendicular to said drive shaft, a crown gear engaging said piniongear and being drivingly connected to and coaxial with said drive shaft,an indicator wheel having an outer surface with indicia thereon forindicating the frequency to which the tuning elements positioned by saiddrive shaft are tuned, said indicator wheel having gear teeth on oneedge of said outer surface thereof in engagement with said pinion gearand turning said indicator wheel in a predetermined relationship torotation of said drive shaft in response to rotation of said piniongear, said indicator wheel being axially displaceable to. disengage saidteeth from said pinion gear and permit said indicator member to beturned freely for calibration, a manually rotatable knurled knob forcontrol of the tuner, a rubber surfaced pinion wheel in engagement withsaid knurled knob and rotatable thereby, said a slip clutch couplingsaid pinion wheel to said pinion gear and causing said pinion wheel toturn said pinion gear and-position the tuning elements between the firstand second positions, said slip clutch permitting said pin-ion wheel toturn with respect to said pinion gear when said pinion gear isstationary at the first and second positions of the tuning elements.

8. A wave signal tuner including in combination, a tuner drive shaftrotatable to position tuning elements between first and secondpositions, control means for rotating said drive shaft, said controlmeans including a first gear having an axis of rotation substantiallyperpendicular to said drive shaft, a second gear engaging said firstgear and drivingly connected to said drive shaft, a manually rotatableknob for controlling said tuner and having a knurled periphery, a pinionwheel having a resilient periphery in engagement with said periphery ofsaid knob to be rotatabile therebyyand means including a slip clutchcoupling said pinion wheel to said first gear to cause said pinion wheelto turn said first gear and position said tuning element-s between thefirst and second positions, said slip clutch permitting s-aid pinionwheel to turn with respect to said first gear when said first gear isstationary at the first and second positions of the tunin-g elements andsaid knob is rotated.

' References Cited by the Examiner UNITED STATES PATENTS 1,601,96810/1926 Huth 74 10.s 2,523,032 9/1950 La Flamme 74 10.s 3,106,09810/1963 Race 74-10.s

MILTON KAUFMAN, Primary Examiner.

8. A WAVE SIGNAL TUNER INCLUDING IN COMBINATION, A TURNER DRIVE SHAFT ROTATABLE TO POSITION TUNING ELEMENTS BETWEEN FIRST AND SECOND POSITIONS, CONTROL MEANS FOR ROTATING SAID DRIVE SHAFT, SAID CONTROL MEANS INCLUDING A FIRST GEAR HAVING AN AXIS OF ROTATION SUBSTANTIALLY PERPENDICULAR TO SAID DRIVE SHAFT, A SECOND GEAR ENGAGING SAID FIRST GEAR AND DRIVINGLY CONNECTED TO SAID DRIVE SHAFT, A MANUALLY ROTATABLE KNOB FOR CONTROLLING SAID TURNER AND HAVING A KNURLED PERIPHERY, A PINION WHEEL HAVING A RESILIENT PERIPHERY IN ENGAGEMENT WITH SAID PERIPHERY OF SAID KNOB TO BE ROTATABLE THEREBY, AND MEANS INCLUDING A SLIP COUPLING SAID PINION WHEEL TO SAID FIRST GEAR TO CAUSE SAID PINION ELEMENTS BETWEEN THE FIRST AND SECOND TION AND TUNING ELEMENTS BETWEEN THE FIRST AND SECOND POSITIONS, SAID SLIP CLUTCH PERMITTING SAID PINION WHEEL TO TURN WITH RESPECT TO SAID FIRST GEAR WHEN SAID FIRST GEAR IS STATIONARY AT THE FIRST AND SECOND POSITIONS OF THE TUNING ELEMENTS AND SAID KNOB IS ROTATED. 